Briefs: CO2 heat pumps in a retirement home

Villa Laura, a retirement home near Florence, Italy, is equipped with 4 water/water ground-water heat pumps operating with a transcritical CO2 cycle providing heating, air conditioning and hot water. This technology is already used to produce hot water for individual housing, particularly in Japan but it seems to be giving good results in installations requiring higher capacities, as in Villa Laura, which covers 4500 m2, on 3 storeys. Blue-Wave, the company providing this system, promises it will halve energy consumption compared with a traditional water-heater plus air-conditioning system. The 4 reversible heat pumps provide 215 kW refrigerating capacity and 240 kW thermal capacity. They operate at 110 bars on the high-pressure side and 40 bars on the low-pressure side, have a gas cooler but no condenser, are coupled with an automatically regulated 1200 kW ice-storage system. In order to improve the energy efficiency of the hot water production, the transcritical cycle operates with an important difference between inlet and outlet temperatures and with heat exchangers whose heat-exchange surfaces were sized accordingly.